Morphometric Analysis of Dinosaur Tracks from Southwest Arkansas

Dinosaur trackways were discovered in Cretaceous De Queen Limestone strata in Howard County, Arkansas, in June 2011. Multiple trackways with variably sized tridactyl tracks were exposed in a commercial quarry, suggesting multiple theropod species or adult and juvenile tracks of a single species. Results of morphometric analyses of 32 plaster casts from selected trackways are reported in an effort to identify the specific track-making dinosaurs and differentiate large and small tracks. Track measurements included length and width of each track, the lengths and widths of each digit impression, and the angular spread (divarication) between digit impressions. Twenty-nine plaster casts were of tridactyl theropod tracks whereas three casts were of poorly preserved tracks of a presumed but unknown tetradactyl (and possibly tetrapod) organism. Plaster casts of tridactyl theropod tracks ranged from 0.36 to 0.61 m long and 0.22 to 0.54 m wide. The longest digit impression on each track was the second, or middle, digit (range = 0.15 – 0.35 m long) with total digit divarication ranging from 31 - 57 degrees. The Arkansas track measurements were compared to tracks (Eubrontes glenrosensis Shuler 1935) preserved in the correlative Glen Rose Formation, Texas and attributed to the large Early Cretaceous carnosaur, Acrocanthosaurus atokensis. The E. glenrosensis track measurements from Texas plotted within the Arkansas data range, suggesting affinity of the Arkansas tracks to E. glenrosensis. Relatively poor preservation of tetradactyl tracks precluded morphometric analysis, but visual comparison to known Cretaceous crocodilian tracks is suggestive of affinity to such organisms

Building the Emotionally Learned Negotiator

This piece reviews three recent books on the significance of emotion in negotiation and dispute resolution (Fisher & Shapiro: Beyond Reason: Using Emotions as You Negotiate; Peter Ladd: Mediation, Conciliation and Emotion: A Practitioner\u27s Guide for Understanding Emotions in Dispute Resolution; and Lacey Smith: Get It! Street-Smart Negotiation at Work: How Emotions Get You What You Want), situating each work within a theory of practice for emotionally learned negotiators. After discussing the how the appearance of emotional sterility became synonymous with professionalism (and the toll this has taken on professional interaction), the piece sets forth a functional theory of emotion in negotiation based on four elements: emotion as (1) ether, (2) obstacle, (3) episteme, and (4) instrument. To cast emotion as ether (the ether of human experience) is to understand the inevitability of emotional impacts on negotiated exchange. For many, emotion in negotiation is encountered as an obstacle (that which obstructs mechanical application of established negotiating techniques). The more sophisticated negotiator recognizes emotionality as episteme (the medium of insight by which we consult interests and hypothesize about others) - a means for better understanding herself, the people she deals with, and a good deal else about the world. Finally, the emotionally learned negotiator uses emotion not only epistemologically but also instrumentally (as a tool for achieving desired ends), taking affirmative steps to help manage the emotional climate within a negotiation. She uses her emotional skills to mitigate undesired emotions and engender preferred emotions within herself and other participants: to soothe, bolster, win respect, build trust, and encourage creativity. The emotionally learned negotiator thus uses emotions not only as tools of knowing, but as instruments of persuasion. The new series of books on the subject offer strategies by which negotiators can learn to better integrate emotional skills into negotiation, among the most emotionally-charged of professional spheres. While the three books share the central premise that emotionality plays a critical role in the unfolding dynamics of all negotiations, each offers its own primary lesson. Lacey Smith\u27s business-oriented Get It! examines how the emotions of hope and fear can be both tools and obstacles to the interest-based bargaining method we first learned in Roger Fisher\u27s classic, Getting to Yes. Fisher and Shapiro\u27s Beyond Reason takes the Getting to Yes method to the next level of sophistication, providing a taxonomy of core emotional concerns that underlie individual negotiators\u27 behavior, and with it a Seven-Elements - like structure from which to prepare, advance, and overcome emotional obstacles in each negotiating context. Peter Ladd\u27s Mediation, Conciliation and Emotions expands the analysis of emotional content in a negotiation from the individual to the shared experience, exploring the establishment of emotional climates that arise between individuals and offering empirically based counsel for mediators and conciliators about how to help remedy undesirable emotional climates and create emotional climates more conducive to problem-solving. No book has all the answers we need, but each makes a valuable contribution to the field

A Method of Altering Coronal Plane Prosthetic Foot Stiffness for Studying its Effect on Amputee Gait

In an effort to understand the effects of prosthetic foot stiffness on amputee gait and mobility, it is useful to produce prototype prosthetic feet that differ in stiffness. While many commercial prosthetic feet are made out of carbon fiber, the manufacturing process is ill-suited to design experimentation as it is expensive, time consuming and requires tooling modifications to produce design changes. In order to facilitate a study of the effects of coronal plane prosthetic foot stiffness on amputee maneuvering gait, we are manufacturing custom prosthetic feet using a form of additive manufacturing, selective laser sintering (SLS), that was developed at the University of Texas at Austin. We have previously used SLS technology to create functional transtibial prosthetic sockets, ankle-foot orthoses, and prosthetic foot prototypes. To manufacture prosthetic feet with different stiffnesses, we first measured the stiffness profile of a commercially available carbon fiber prosthetic foot on an Instron 3345 (Norwood, MA) in two configurations where the foot was loaded to 114 kg in foot flat at 0° eversion and toe-only at 5° eversion positions. A computer aided design model of an SLS prosthetic foot was developed and adjusted to match the stiffness profile of the carbon fiber foot. Finite element analysis (SolidWorks Corp.; Waltham, MA) was then used to verify that the desired stiffness level was achieved. This process was repeated to create three prosthetic feet with altered coronal plane stiffness profiles (25% greater, 50% greater, and 25% less) while sagittal stiffness was held constant. The prototype feet were fabricated using selective laser sintering in a Vanguard HiQ/HS SLS Machine (3D Systems Corp.; Rock Hill, SC). Finally, the feet were mechanically tested in the same configurations as the carbon fiber foot to confirm that they had the desired stiffness profiles. Prototype feet closely matched the sagittal stiffness of the chosen prosthetic foot while coronal plane stiffnesses were approximately the same, 30% greater and 30% less than the carbon fiber foot. Future work will be to use these feet to observe the influence of coronal plane stiffness on amputee gait

Coronary Artery Reperfusion

The effects of coronary artery reperfusion 3 hr after coronary occlusion on contractile function and the development of myocardial damage at 24 hr was studied experimentally. In 14 control and 6 reperfused dogs, relationships between epicardial ST segment elevation 15 min after coronary occlusion and myocardial creatine phosphokinase activity (CPK) and histologic appearance 24 hr later were examined. The electrocardiograms were recorded from 10 to 15 sites on the left ventricular epicardium and transmural samples for CPK and histology were obtained from the same sites where epicardial electrocardiograms had been recorded. An inverse relation existed between ST segment elevation (mv) 15 min after occlusion and log CPK activity (IU/ mg of protein) 24 hr later, log CPK = - 0.06ST + 1.26. In dogs subjected to coronary artery reperfusion, there was significantly less CPK depression (log CPK = - 0.01ST + 1.31, [P < 0.01]) than that expected from the control group. In the control group 97% of specimens showing ST segment elevations over 2 mv at 15 min showed abnormal histology 24 hr later. In contrast, in the reperfused group 43% of sites exhibiting elevated ST segment at 15 min showed abnormal histology 24 hr later. In six additional dogs it was shown that the paradoxical movement of the left ventricular wall could be reversed within 1 hr of perfusion. Therefore, by enzymatic and histologic criteria, as well as by functional assessment, coronary artery reperfusion 3 hr after occlusion resulted in salvage of myocardial tissue

A test of non-equilibrium thermodynamics in glassy systems: the soft-sphere case

The scaling properties of the soft-sphere potential allow the derivation of an exact expression for the pressure of a frozen liquid, i.e., the pressure corresponding to configurations which are local minima in its multidimensional potential energy landscape. The existence of such a relation offers the unique possibility for testing the recently proposed extension of the liquid free energy to glassy out-of-equilibrium conditions and the associated expression for the temperature of the configurational degrees of freedom. We demonstrate that the non-equilibrium free energy provides an exact description of the soft-sphere pressure in glass states

Volume Effects on the Glass Transition Dynamics

The role of jamming (steric constraints) and its relationship to the available volume is addressed by examining the effect that certain modifications of a glass-former have on the ratio of its isochoric and isobaric activation enthalpies. This ratio reflects the relative contribution of volume (density) and temperature (thermal energy) to the temperature-dependence of the relaxation times of liquids and polymers. We find that an increase in the available volume confers a stronger volume-dependence to the relaxation dynamics, a result at odds with free volume interpretations of the glass transition.Comment: 9 pages 5 figure

Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean

This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the Soufrière Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features

Potential energy landscape-based extended van der Waals equation

The inherent structures ({\it IS}) are the local minima of the potential energy surface or landscape, $U({\bf r})$, of an {\it N} atom system. Stillinger has given an exact {\it IS} formulation of thermodynamics. Here the implications for the equation of state are investigated. It is shown that the van der Waals ({\it vdW}) equation, with density-dependent $a$ and $b$ coefficients, holds on the high-temperature plateau of the averaged {\it IS} energy. However, an additional ``landscape'' contribution to the pressure is found at lower $T$. The resulting extended {\it vdW} equation, unlike the original, is capable of yielding a water-like density anomaly, flat isotherms in the coexistence region {\it vs} {\it vdW} loops, and several other desirable features. The plateau energy, the width of the distribution of {\it IS}, and the ``top of the landscape'' temperature are simulated over a broad reduced density range, $2.0 \ge \rho \ge 0.20$, in the Lennard-Jones fluid. Fits to the data yield an explicit equation of state, which is argued to be useful at high density; it nevertheless reproduces the known values of $a$ and $b$ at the critical point

Stratospheric ozone chemistry feedbacks are not critical for the determination of climate sensitivity in CESM1(WACCM)

The Community Earth System Model‐Whole Atmosphere Community Climate Model (CESM1‐WACCM) is used to assess the importance of including chemistry feedbacks in determining the equilibrium climate sensitivity (ECS). Two 4×CO2 model experiments were conducted: one with interactive chemistry and one with chemical constituents other than CO2 held fixed at their preindustrial values. The ECS determined from these two experiments agrees to within 0.01 K. Similarly, the net feedback parameter agrees to within 0.01 W m−2 K−1. This agreement occurs in spite of large changes in stratospheric ozone found in the simulation with interactive chemistry: a 30% decrease in the tropical lower stratosphere and a 40% increase in the upper stratosphere, broadly consistent with other published estimates. Off‐line radiative transfer calculations show that ozone changes alone account for the difference in radiative forcing. We conclude that at least for determining global climate sensitivity metrics, the exclusion of chemistry feedbacks is not a critical source of error in CESM